The present invention relates to a method for the input of a trace starting point of an image and, more particularly, to a method for the input of a trace starting point of an image, so adapted as to enter the trace starting point of the image with high efficiency in order to allow a CAD (a computer-aided design) machine, etc. to take effective advantage of a semi-automatically image-trace processing function for semi-automatically tracing a continuous pixel sequence of image data.
Heretofore, the method for the input of a drawing drawn on paper into an image processing system generally comprises inputting of the drawing as image data by an image scanner or the like, displaying the image data on a display screen by an image processing system, and allowing the operator to enter a continuous pixel sequence of the image manually through a pointing device while looking at the display screen.
For example, Japanese Patent Laid-open Publication (kokai) No. 269,276/1987 discloses a method of the input of a drawing in a conversational mode, which comprises entering the drawing into a computer system as image data through a scanner, superimposing the resulting image data on center-line image data, and entering the drawing as vector data representing the drawing with coordinate points by specifying necessary positions of the drawing on the display screen with a coordinate pointer.
For example, when the image data is converted into graphic data such as vector data, etc. as described hereinabove, central data on the center or the center line of the image is given, data on necessary characteristic points of the continuous image, such as end points, branch points, corner points, etc. is selected and specified from the central data, and such data is entered. In this case, in order to enter the characteristic points, the central data is superimposed on the image data on the display screen to allow the operator to judge the characteristic points with ease, and the characteristic points are entered manually by the operator. Hence, this input method suffers from the disadvantage that the display screen becomes so complex that the operator cannot select the necessary data with high efficiency.
On the other hand, there has been developed an image processing device with a semi-automatically image-trace processing function that traces a line image of image data, i.e. a continuous pixel sequence thereof, in a semi-automatic fashion, determines the characteristic points, and enters the graphic data of the characteristic points. It is to be noted herein that an instruction to enter a point on the line image to be traced is entered by specifying a point on the line image by employing such a semi-automatically image-trace processing function of the image processing device.
However, the conventional image processing device with the semi-automatically image-trace processing function does not pay much attention to the fact that the trace starting point of the image to be traced is entered with efficiency in the trace processing of the continuous pixel sequence of the image data. Hence, all of the trace starting points of the line image to be traced should be specified and entered one after another by setting the accurate positions of the points on the line image with an input device such as a pointing device or the like. This input operation is extremely laborious.